Work will be continued on the following problems: 1. The solubilization, resolution and reconstitution of transport-active membrane vesicles from pigeon red cell membranes. 2. The transport-induced separation of transport-active membrane vesicles from less active or inactive vesicles. This is aimed at assessing the extent of association of different transport or other activities in discrete domains. 3. The preparation of hybrid membrane vesicles from membrane and added lipids which retain membrane activities.